3. Rowling says in the entry that the name Celestina came from a friend with whom she worked at Amnesty International.

As well as talking about the “glamorous” witch’s Hogwarts house, wand, family, and hobbies, Rowling goes on to describe how popular Celestina really is:

Three devoted fans were involved in a nasty three-broom pile up over Liverpool while trying to reach the last night of her Flighty Aphrodite tour, and her tickets often appear on the black market at vastly inflated prices (one reason why Molly Weasley has never yet seen her favourite singer live).